Process of treating borax ores.



- H. BLUMENBERG.

PROCESS OF TREATING BORAX 0358.

I APPLICATION FILED NOVPIGI I916- 3,25,71 4 Patented Mar. 19, 1918.

1N veuroe Henr B! umnbmcg E STATE @ATENT @FFTQE.

{HENRY BLUMENBERG, or LOS ANGELES, cnmronma, ASSIGNOR 'ro cmrronn I. HINMAN, 013 Los ANGELES, CALIFORNIA.

1,259,718. Original application filed April 26, 1916,

To all whom it may concern:

Be it known that I, HENRY BLUMENBERG, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented new and useful Improvements in Processes of Treating Borax Ores, of which the following is a specification. i

My invention relates to a process of treating borax ores such as the borates of the alkali and alkaline earth metals, likewise the bore silicates of the alkali and alkaline earth metals.

It is a well known fact that at the present time, the calcium boro-silicates cannot be profitably concentrated for commercial purposes owing to the excessive cost of extracting the boric acid from this class of ores; neither can the low grade calcium borate ores such as pandermite Ca B O +4H O and sodium boro-calcite be successfully treated for the same reasons. cium borate in the United States is mined in California, and the largest consumption of borax is on the Atlantic coast. The best known practical commercial method of decomposing calcium borate is by roasting which is expensive and is limited to the calcium borate solely, as the calcium boro-silicates as a rule do not contain boric acid in sufficient quantities to make the roasting process profitable.

My novel method comprises dissolving the ore in nitric acid, thereby producing calcium nitrate and boric acid and mixing the boric acid with sodium nitrate, producing sodiumborate and nitric acid, the latter of which may be used for dissolving the ore for producing another batch of calcium nitrate and boric acid. The great practical advantage of my process consists in the fact that from the ores may" be produced either boric acid or borax; no crushing, grinding or roasting at a high temperature is necessary; the decomposing agent can be used over and over again, or sold as calcium nitrate at a better price than its original cost, as sodium'nitrate. Furthermore, the end product has at least double the boric acid contents of the products produced by the present methods, thus reducing the transportation charges to the point of consump- Specification of Letters Patent.

Mostly all the cal- I Patented. Mar. 19, 1918.

Serial No. 93,763. Divided and this-app1ication filed November 16, 1916. Serial No. 181,785.

tion. In the refining of my product by crystallization, a large part of the filter press expense is eliminated, as there is very little lime cake to handle.

My process is practical and economical for thereason that calcium nitrate gives up its nitrogen. oxids at a low temperature while all the other known methods which use sulfuric, sulfurous and hydrochloric acids leave by-products that have practically no commercial value. Furthermore, the old methods involve the use of excessive heat, thereby destroying the apparatus, and likewise increasing the expense of operation. other advantage of my process is the latitude, allowing any products to be produced to suit the market conditions, to wit, borax, boric acid, lime, nitric acid and calcium nitrate.

The present case is a divisional application of my application for U. S. Letters Pat-- out, for a process of treating borax ores,

Serial Number 93763, filed the treatment while the present case has its claims limited to the production" of calcium nitrate, While another divisional application of the parent case, filed of even date" Number 131,786, has its claims limited to the treatment of borax ores with sodium nitrate.

My invention will be better understood with the aid of the accompanying drawings which illustrate diagrammatically the apparatus used for carryingout my process.

The crushed borax ore is introduced in a. closed predigester tank 10 where it is treated with a weak solution of nitric acid. valved outlet pipe 11 leadsfrom the bottom of tank 10 to the main digester 12 where the ore is treated with a strong solution of nitric acid, which acting upon the calcium borate will form calcium nitrate and boric acid. The ore will be dissolved to such an extent that the same may be easily handled by a. pump 13 pumping the treated ore in solution from the bottom of the digester 12 to a filter press 14. 15 designates the pipe line leading from the bottom of the digester 12 to the pump 13, while 16 designates the pipe line leading from said pump to the filter press April 26, 1916., The claims in the parent case are drawn tr p, of borax ores with nitric acid;

herewith, Serial 14. The filtrate is led from the filter press 66 23, and operating thesuction pump 25. By-

14 to a steam jacketed evaporating tank or crystallizer 17 Owing to the fact that boric acid is sparingly soluble in water while calcium nitrate is highly soluble the boric acid on cooling will crystallize outand may be removed from the evaporating pan to a drying platform 18.

The boric acidif so desired may be used as the end product and the calcium nitrate may be concentrated and mixed with calcium oxid and evaporated to dryness to form a basic calcium nitrate.

If it is desired to make borax, the boric acid is moved from the dryin platform 18 to a mixing floor 19 Where it Is mixed with sodium nitrate in. proper proportions so that the sodium of the nitrate will be of the proper amount to form borax glass. The mixture of boric acid and sodium nitrate is conveyed from the mixing floor by suitable conveying means 20 to a hopper 21' leading to a converter 22. The converter is pro vided with suitable heating means such as a fuel nozzle 23. By heating the mixture of boric acid and sodium nitrate, and nitric acid will be formed.

The nitric acid radical of the sodium nitrate combines with the hydrogen of the boric acid and will be driven ofi. The nitric acid fumes are led from the converter 22 by a pipeline 24 into the digester 12 where the nitric acid borax glass fumes will be absorbed by the water therein,

and are utilized for treating another batch of borax ores. An exhaust pump 25 is operated to produce a partial vacuum of seven and one-half pounds to the square inch. The pump 25 is operatively connected to the digester 12 by means of a pipe line 26'leading rom said vacuum pump to the top of the predigester 10., The pipe line 27 leads from the top of the digester 12 to near the bottom of the predigester 10. It is thus seen that the suction of the vacuum pump 25 will cause the nitric acid and nitrogen oxid fumes from the converter 22 to pass to the digester 12 and will suck any oxid fumes which may collect at the top of the digester 12 to the predige'ster 10 in which practlcall all the nitrogen oxid fumes will be absorbed. In order to reduce any losses by decomposition of the nitrate to a minimum, it is imortant not to exceed a temperature of 1000 egrees O. in the converter 22. Furthermore, the nitrogen oxid and nitric acid q fumes should be mixed with oxygen to convert the lower'nitrogen oxide to the higher 0 ds, and removed asvrapidly as possible from, the converter 22. These conditions are obtained by supplying an excess of air with the air of combustion for the fuel supply oxygen and steam to the nitrogen supplyin by the immediate removal of the OXldS and nitrogen qx1ds, the losses of nitric acid are reduced to a mlnimum.

From the-converter 22, the fused borax glass may be run through a chute 28 to a suitable tank or vessel 29 partially filled with glass may be roasted or calcined, breaking up into calcium oxid and nitrogen oxide which latter as in the case of the production of borax glass are led through the pipe line 24 to the digester 12. The lime is led through the chutes 28 and 32 to a suitable storage place, not shown, or may be used for makin basic calcium nitrate presently to be descri ed.

It may be remarked here that the lime produced by my process is a product of remarkable purity, and in a physical condition that makes it especially adapted for use in sugar refining or the extracting of sugar from molasses. The calcium oxid is flufi'y and is almost chemically pure, and sells from $1.00 to' $2.00 more a ton than the ordinary lime. Southern California has many beet sugar factories which are in the market for lime, my (process has the additional advantage of pro ucing a by-product for which this is a ready market.

If it is desired to use calcium nitrate as a fertilizer, the nitrate in solution is run from the evaporating an 17 through a pipe line 33 to a basic ca cium nitrate pan 34 provided with a steam jacket, where the calcium nitrate solution is mixed with a suitable quantity of lime conveyed thereto through the lime chute 32. By evaporating the mixture of calcium oxid and calcium nitrate, a, basic calcium nitrate, valuable as a fertilizer is formed. Suitable proportions for the basic calcium nitrate are one molecule of each. 35 designates a main steam supply pipe from which a pipe line 36 leads to the. basic. calcium nitrate pan 34 and a pipe line 37 to the interior of the digester 12 and to the steam jacket surrounding the same; from the pipe line 37 a branch pipe 38, leads to the evaporating pan 17.

In view of the fact that the insoluble matter staying in the pressed cake, the soluble nitrates and the boric acid being led to the evaporating pan 17 as in the case of the lime borate ores.

The solution of calcium nitrate when concentrated becomes colloidal and it is diflicult to handle. It is therefore advisable to add from 15 to 25% of calcium oxid t0 the nitrate liquors in the last stages of evaporation in the evaporating pan 17. The resulting basic calcium nitrate may now be evaporated to a friable solid which may be easily manipulated and which has less tendency to absorb moisture than the normal calcium nitrate.

While I have described the best method of treating borax ores as now known to me, it will be understood that I do not limit myself to the particular process described, as various changes may be made by those skilled in the art without departing from the spirit of myinvention. For instance, a mixture of finely ground calcium borate, such as colemanite ore, if heated in the presence of sodium nitrate, would result in a decomposition of this nitrate forming sodium borate and calcium nitrate the whole forming a fused mass. This fused mass is digested with water, and the sodium borate is separated from the calcium nitrate by a process of cooling and crystallization.

It is thus seen that I have devised an economical and flexible process of treating borate ores which yields practically no modifying the steps in the process or usm valueless by-products, and which allows the production of boric acid, borax, lime, calcium nitrate, as market conditions may require without the necessity of materially additional apparatus.

I claim:

1. A process of treating borax ores comprising digesting calcareous borax ores with nitric acid to form calcium nitrate and boric acid, separating the boric acid from the calcium nitrate and heating the calcium nitrate to form calcium oxid and nitrogen oxids and congerting said nitrogen oxids into nitric acl 2. A process of treating borax ores comprising digesting calcareous borax ores with nitric acid to form calcium nitrate and boric acid, separating the boric acid from the calcium nitrate and heating the calcium nitrate to form calcium oxid and nitrogen oxids.

3. A process of treating borax ores, comprising digesting calcareous borax ores with nitric acid to form calcium nitrate and boric acid, filtering the mixture, separating the boric acid from the calcium nitrate and heating the calcium nitrate in a closed chamber in the presence of oxygen and aqueous vapor to form nitric acid and calcium oxid.

In testimony whereof I have signed my name to this specification.

HENRY BLUMENBERG. 

